Coffee beans are roasted seeds from the fruit of the evergreen tree. Like other nuts and seeds, they are high in proteins (11 percent), sucrose and other sugars (8 percent), oils (10 to 15 percent, assorted organic acids (6 percent), B vitamins, iron, and the central nervous system stimulant caffeine (1 to 2 percent). With the exception of caffeine, none of these nutrients is found in coffee. Coffee contains oxalic acid (which binds calcium ions into insoluble compounds your body cannot absorb), but this is of no nutritional consequence as long as your diet contains adequate amounts of calcium-rich foods.

Coffee's best known constituent is the methylxanthine central nervous system stimulant caffeine. How much caffeine you get in a cup of coffee depends on how the coffee was processed and brewed. Caffeine is water-soluble. Instant, freeze-dried, and decaffeinated coffees all have less caffeine than plain ground roasted coffee.

Adverse effects. In 1994, researchers at the Agricultural University in the Netherlands identified two chemicals in coffee that may raise cholesterol levels. The chemicals, cafestol and kahweol, are members of a chemical family called diterpenes in coffee oils. The amount of diterpenes varies with the brewing method. Drip-brewed coffee, instant coffee, and percolated coffee contain only minimal amounts of diterpenes. Boiled coffees, such as Greek, Turkish, espresso, and those made in a French "press" coffeemaker, may have 6 to 12 mg diterpenes in a 5-ounce cup. The Dutch researchers estimate that drinking five cups of press-brewed coffee or 15 espressos a day might raise cholesterol levels 8 to 10 points.

A 1997 study found that even moderate coffee consumption (five or fewer cups a day) is linked to higher blood levels of homocysteine. This may explain the results of a 1995 study at Boston University School of Public Health, showing the risk of heart attack 2.5 times higher among women who drank 10 cups of coffee a day than among those who averaged less than one cup.

Caffeine slows the flow of blood to the placenta, makes the fetal heart beat faster, and lowers the level of estradiol in a pregnant woman's body. A number of epidemiological human studies suggest that consuming more than 300 mg caffeine a day, about the amount in three cups of coffee, may slightly increase the risk of spontaneous abortion or giving birth to a low birthweight infant or one with microcephaly (an abnormally small head and brain).

<<Back

Source: http://www.worldroom.com/pages/shelves/offshlvjul14.phtml
NOTE: This article has been edited.